text: // @flow
  
  import luhn from 'luhn-alg'
  
  export const LUHN = 'luhn'
  
  export function validateFormat (value: string, pattern: RegExp): boolean {
    return pattern.test(value)
  }
  
  export function validateChecksum (value: string, algorithm: string): boolean {
    switch (algorithm) {
      case LUHN:
        return luhn(value)
  
      case null:
      case undefined:
        return true
  
      default:
        return false
    }
  }
  